Rotary kiln and cooler



May 14, 1935. P. T. LIN'DHARD' 2,001,258

' ROTARY KILN AND COOLER Filed Dec. 15, 1932 2 Sheets-Sheet 1 INVENTOR May 14, 1935,

P. 1'. LINDHARD ROTARY KILN AND COOLER Filed Dec. 15, 1932 2 Sheets-Sheet 2 TTb NEYs Patented May 14, 1935 UNITED STATES PATIENT OFFICE 'Smidth & 00., New

of New Jersey Yfork, N. Y., a corporation Application December 15, 1932, Serial No. 647,340 In Great Britain September 13, 1932 1 Claim.

This invention relates to rotary kilns and coolers employed in the production of Portland cement and of the general type shown in Letters Patent of the United States No. 1,653,050 and has been developed to meet the requirement for a kiln and cooler of large capacity and capable of reducing the clinker to a temperature of about 150 F.

The construction of a kiln and cooler of this type in which the clinker is carried onward through the cooler tubes in the same direction in which it moves through the kiln itself is not well adapted because of difficulties in construction and in operation, for kilns of such large capacity as that referred to. It has been found, however, in the development of the present invention that a kiln of this general type, but i:\ which the cooler tubes are axially parallel with the kiln and in which the clinker moves in a direction opposite to that in which it moves through the kiln, can be constructed in large size without encountering the difiiculties alluded to. In accordance with the present invention the kiln it self is so formed between the clinkering zone and the lower or discharge end of the kiln as to accelerate the movement of the clinker while the cooler tubes are formed each of a succession of cylindrical sections of successively greater diameter. Through the formation of the kiln as referred to the clinker is not only caused to move more rapidly but is spread out more thinly as it proceeds within the kiln beyond the clinkering zone and thereby undergoes more reduction in temperature before it is discharged from the kiln into the cooler tubes. Because of the axial inclination upward of the cooler tubes provision is made in the sections of smaller diameter to overcome the effect of such inclination and to promote the movement of the .clinker, thereby pre- 0 venting the accumulation of hot clinker in such sections and the destructive efiect of such hot clinker on the cooler tubes themselves if allowed to accumulate, while in the final and largest section of each cooler tube, where the clinker is exposed to the cooling air as it enters the cooler tube at its lowest temperature, the clinker is not only allowed to accumulate and thereby to remain longer in contact with the cooling air, but has its movement retarded by. heat exchanging devices, such as chains. It thus becomes possible to con struct a kiln and cooled of large capacity without meeting serious difiiculties in construction and the temperature of the clinker is reduced to such a degree as that suggested above. Not only is the cooling action thus made highly effective, but the walls of the cooler tubes will be little subjected to the destructive action of heat from the hot clinker.

The invention will be more fully explained hereinafter with reference to the accompanying 5 drawings in which it isillustrated, and in which:'

Figure 1 is a view, partly in elevation and partly in section, of a kiln and cooler tubes constructed in accordance with the invention.

Figure 2 is a view in section of one of the cooler tubes, on a larger scale than that of Figure 1.

Figures 3, 4 and 5 are views in section on the planes indicated by the broken lines 33, 4-4 and 5-5 of Figure 2.

The kiln a, which, except as hereinafter indicated, may be constructed as'usual, having a slight downward pitch toward the lower or discharge end, is arranged to be supported and to be rotated in the usual manner. It is provided, as at b, with a movable hood through which extends the fuel delivery pipe c, the inner end of which marks approximately the lower end of the clinkering zone. The kiln is provided interiorlywith a refractory lining d which maybe reduced in thickness from the end of the clinkering zone toward the outlet end, the shell of the kiln beyond the clinkering zone, as at e, being enlarged in diameter. The interior of the kiln, below or beyond the clinkering zone, is thus progressively enlarged so that, in the ordinary operation of the kiln the clinker is spread out more thinly as it leaves the clinkering zone and has its movement accelerated thereby losing some of its heat in this portion of the kiln which has a temperature much lower than that of the clinkering zone. Near the lower end of the kiln it is provided with outlet chutes f which serve to conduct the hot clinker from the interior of the kiln to the cooler tubes to be described, such chutes being provided exteriorly with radiating fins f for the purpose of radiating as much as possible of the heat communicated by the hot clinker and of preserving them from the destructive action of the heat.

Each cooler tube, in the embodiment of the invention shown, is formed of a succession of cylindrical sections g, h and i, axially parallel with the kiln itself and suitably secured to the kiln, as at e and e so that the tubes revolve with the kiln. The several sections may be stepped 50 abruptly, as shown.

The smallest section 9, into which the hot clinker, in the rotation of the kiln, is first discharged from the kiln and is therefore subjected to relatively high temperature, is provided ex- 6 2 teriorly with radiating flns a to cool as much as possible the walls of the section and prevent the destructive action of the heat. This section is provided interiorly with conveyor flights a for the purpose of promoting the movement of the hot clinker through the section, notwith standing its upward axial inclination. The flights g are provided on one face with radiating flns for the purpose of radiating as rapidly as possible the heat transmitted to the flights from the clinker with which-they are in contact on their other faces. At the discharge end of the section a are provided distributor flights a which serve to guide the clinker discharged from the section a into the next section h in several streams. The section h, also cylindrical but of larger diameter than the section g, is provided with lifters n which are preferably increased in width from one end to the other and are preferably serrated at theirinner edges and thereby, in the revolution of the cooler tubes, the clinker is elevated and at the same time distributed and allowed to fall through the cooling air in its passage toward the kiln. Distributor and conveyor flights it serve to conduct the now somewhat cooled clinker from the section It into the section i, which may be provided with relatively narrow conveyor flights to overcome the upward inclination of the cooler tubes and prevent excessive accumulation of the clinker and also with heat transferring devices, such'as chains i to promote the further cooling of theclinker and also to delaysomewhat the movement of the clinker through this section so that it shall the longer remain in contact with the cooling air which enters the open end of the section through which the relatively cool clinker is discharged.

The operation of the improved kiln and cooler will be understood without further explanation and it will also be understood-that the number of sections of each cooler tube can be varied to suit diflerent conditions of use and that the invention, except as pointed out in the accompanying claim, is not restricted to the. particular construction shown and described herein.

I claim as my invention:

The combination of a rotary cement kiln having a downward pitch toward the discharge end and having its lower portion below the clinkering zone gradually enlarged in diameter interiorly, whereby the movement of, the. clinker is accelerated and the clinker is partially cooled, and provided beyond-the enlarged portion with delivery chutes, and cooler tubes into which the clinker is delivered from the kiln through the delivery chutes, each cooler tube consisting of a succession of cylindrical sections of successively larger diameters stepped abruptly and open at the larger and upper end for the admission of cooling air and the discharge of the clinker and each cooler tube being axially parallel with the kiln, whereby the movement of the clinker through each cooler tube is delayed progressively and contact with the cooling air is extended.

POVL T. LlNDHARD. 

